---------------------------------------------------------- Kitfox-List Digest Archive --- Total Messages Posted Fri 01/21/11: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 02:35 AM - Composites and mold work (WurlyBird) 2. 05:52 AM - Re: Composites and mold work (Mike Chaney) 3. 08:41 AM - Re: Composites and mold work (Guy Buchanan) 4. 09:53 PM - Re: Composites and mold work (WurlyBird) ________________________________ Message 1 _____________________________________ Time: 02:35:24 AM PST US Subject: Kitfox-List: Composites and mold work From: "WurlyBird" I am sure there are some people on here with a good amount of experience with composites and I have a few questions for you. I am looking to make a few parts for my plane when I get home and I want to play with composites and molds. One of my biggest concerns is with preparing a mold properly, everything I have been reading involves waxing the mold with several layers and then spraying with a mold release. Is there any type of mold release that skips the waxing step? I am considering using some molds with a lot of sharp inside corners so I am concerned about not getting enough wax on and a spray would be much more convenient. There are countless resin combinations available. Are any of them better suited to mold work? I plan on doing some work with carbon fiber for aesthetics, are some resins better for this as far as coloring goes? I have seen some resins claim to be more clear then others. I have also seen mention of UV protection. Still trying to figure all this out so any insight is appreciated. Does anyone have a preferred method for pulling a plug from an existing part? The techniques I have read most about and am leaning towards is gel coat painted over the part and then backed with a two part mold putty or fiberglass for strength. I am sure I will think of more of the questions rolling around in my head after responses. In the mean time thanks for any input. -------- James Kitfox 3 / 582 / 70" IVO 2 blade GA 50 hrs on the Fox in between deployments, now she lies in wait Read this topic online here: http://forums.matronics.com/viewtopic.php?p=327758#327758 ________________________________ Message 2 _____________________________________ Time: 05:52:13 AM PST US From: Mike Chaney Subject: Re: Kitfox-List: Composites and mold work James - Check out www.fibreglast.com for information concerning composite work.- They are a supplier of products and they also have a section on this websit e with demonstrations.- I've ordered from them in the past. - Mike - Kitfox IV Jabiru 2200 --- On Fri, 1/21/11, WurlyBird wrote: From: WurlyBird Subject: Kitfox-List: Composites and mold work l> I am sure there are some people on here with a good amount of experience wi th composites and I have a few questions for you.- -------- James Kitfox 3 / 582 / 70" IVO 2 blade GA 50 hrs on the Fox in between deployments, - - - now she lies in wait Read this topic online here: http://forums.matronics.com/viewtopic.php?p=327758#327758 le, List Admin. =0A=0A=0A ________________________________ Message 3 _____________________________________ Time: 08:41:25 AM PST US From: Guy Buchanan Subject: Re: Kitfox-List: Composites and mold work On 1/21/2011 2:32 AM, WurlyBird wrote: > One of my biggest concerns is with preparing a mold properly, > I've never seen a reliable mold release that's a simple spray-on. I and the professionals I've worked with have always done 6-8 layers of wax plus PVA mold release. Done correctly you won't have corner build-up. You'll want to minimize sharp corners, particularly for hand-laid parts. The various woven goods just don't like to turn corners very sharply so you'll be forced to vacuum bag. Otherwise, you'll have to use a milled fiber build-up (fillet) in the corner and have the cloth turn inside that which leaves the corner material relatively weak and not very aesthetic. > There are countless resin combinations available. Are any of them better suited to mold work? I plan on doing some work with carbon fiber for aesthetics, are some resins better for this as far as coloring goes? I have seen some resins claim to be more clear then others. I have also seen mention of UV protection. Still trying to figure all this out so any insight is appreciated. > The resin you use for tooling depends on how you intend to cure the part. In general you want a very long pot life and slow, low temperature cure for tooling because molds are thick and relatively unstable. If you intend to heat cure the part you may will want a tooling resin that you can post cure at an elevated temperature so it remains stable when you cook the part. See http://www.ptm-w.com/dynamicdata/data/docs/pt2520%20bulletin.pdf for a likely tooling resin. For parts I like the System-Three Silver Tip series for clarity. You're right that some are clearer than others. You hint that you'll be leaving the part natural. For UV protection I rely on the clear-coat I use over the cured part. I use Stirling urethane clear coats because they're very, very clear and spray on nicely. Expensive, though. I saw that they have clear gel-coat now so I suppose it's possible to pull a "finished" part from a tool, though I've never seen it done and don't know how clear clear gel-coat is. One more note on clear carbon parts. As you probably well know black surfaces get quite hot in the sun. It's possible for black painted steel to get up to over 250F in the sun. You're clear-coated carbon part will also get quite hot if it's exposed to direct sunlight. This means your part will have to be cured at least somewhere near the service temperature so it doesn't get all soggy in the sun. This means your tool will have to be able to withstand an elevated cure temperature without getting all soggy. When I did my clear carbon glare shield I cured it at 140F on the tool using a black bag and hot air blower, then I post cured it at 250F in a crude foam insulation oven with hot-air blower. > Does anyone have a preferred method for pulling a plug from an existing part? The techniques I have read most about and am leaning towards is gel coat painted over the part and then backed with a two part mold putty or fiberglass for strength. > You've got it, though don't forget the mold-release. ;-) Guy Buchanan Ramona, CA Kitfox IV-1200 / 592-C / Warp 3cs / 500 hrs. and grounded ________________________________ Message 4 _____________________________________ Time: 09:53:52 PM PST US Subject: Kitfox-List: Re: Composites and mold work From: "WurlyBird" Thanks for the great information. Here is the first followup question. What does baking a composite part do to the build up? Does heating the resin while it is curing cause it to more thoroughly cure? From the way you phrased it it sounds like if you expect your part to be exposed to 200 deg in use then it should be baked at a minimum of 200 deg during build up, is this about right? I do plan on leaving some of the parts natural. If I get the HKS when I get home I am going to need a new instrument panel and I figure it might as well be carbon or carbon/kevlar. Light, functional, and sexy, you cant beat it. With the Kitfox being as low tech and old school as it is, I anticipate that the carbon on the dash will look a little out of place so there will need to be a little carbon here and a little there just to balance it out aesthetically. I am conceiving a part that will be a LOT of sharp corners but I plan on getting into bagging and maybe even infusion. If the part I have in my head works out I will be telling you all about it, until then it is hush hush. In case anyone else has been toying with the idea of bagging but can not find a reasonable set up, check this out: http://www.veneersupplies.com/ http://www.joewoodworker.com/ Joe Woodworker has designed and has free plans for venturi style vacuum press and vennersupplies sells the kit. This set up has the benefit of having a vacuum reservoir that can easily be made a little larger and even as published should be great for dash sized projects. -------- James Kitfox 3 / 582 / 70" IVO 2 blade GA 50 hrs on the Fox in between deployments, now she lies in wait Read this topic online here: http://forums.matronics.com/viewtopic.php?p=327856#327856 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message kitfox-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Kitfox-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/kitfox-list Browse Digests http://www.matronics.com/digest/kitfox-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.